中文摘要：

目的观察地塞米松（dexamethasone，Dex）对培养的脊髓背角星形胶质细胞内游离ca2＋浓度（[ca2＋]i）的影响，并初步探讨其作用机制。方法培养纯化新生SD大鼠脊髓背角星形胶质细胞，激光共聚焦显微镜检测星形胶质细胞[ca2＋]，的变化。结果Dex可导致培养的脊髓背角星形胶质细胞[ca2＋]．快速升高，且呈现剂量依赖性（P〈0．05）；Dex诱导的星形胶质细胞[ca2＋]；升高是以外钙内流为主；G蛋白阻断剂百日咳毒素（100ng／mL）可阻断Dex所致的星形胶质细胞[ca2＋]，升高效应（P〈0．01），而糖皮质激素细胞质可溶性受体（GR）拮抗剂RU38486（10μmol／L）对Dex的效应无影响；此外，蛋白合成抑制剂放线菌酮对Dex所致的星形胶质细胞[ca2＋]i升高效应无阻断作用。结论Dex可能通过由糖皮质激素膜受体介导的非基因组作用途径快速升高脊髓背角星形胶质细胞[ca2＋]i。

英文摘要：

Objective To explore the effect of dexamethasone （Dex） on intracellular calcium concentration （[ Ca2＋]i ） in cultured astrocytes of rat spinal dorsal horn and the relative mechanism. Methods Astrocytes obtained from neonatal SD rat spinal cord were cultured and purified. Changes of [ Ca2＋]i in cultured dorsal spinal cord astrocytes were detected with confocal laser scanning microscopy using fluo-4/AM as a calcium fluorescent indicator. Results Dex induced a rapid elevation of [ Ca2＋] i in the cultured astrocytes within several minutes in a dose-dependent manner （P 〈 0.05）, and the elevation could be blocked by pertussis toxin （PTX, a blocker of G protein activation, 100 ng/mL） rather than by glucocorticoid receptor antagonist RU38486 （10 p.mot/L）. In addition, cycloheximide （CHX, protein-synthesis inhibitor, 10μg/mL） pretreatment could not impair the Dex-induced [ Ca2＋]i elevation. Conclusion These observations suggest that a non- genomic pathway may be involved in the effect of Dex on [ Ca2＋]i elevation in cultured astrocytes of spinal dorsal horn, and the effect may be mediated by G-protein-coupled membrane-bound glucocorticoid receptor （mGCR）.